Dyeing with azo dyes



atented W ii JAMES BADDILEY, PERCY CIEEOBLEY, AND RAINALD BRIGHTMAN, 01E BLAGMIIEY, MAN'- CHESTER, ENGLAND, ASSIGNOBS T0 BRITISH: DYESTUJEFS CORPORATION LIMITED, 015 MANCHESTER, ENGLAND, A COMPANY OF GREAT BRII'JETIN' AND IRELAND prisms wrrn azo n'rns No Drawing". Application filed March 16, 1927, Serial No. 175,926, and in Great Britain September PI, 1926.

By this invention regenerated cellulose silks, such as viscose silk, are dyed in level shades with the dyestuffs obtained by cou pling diazotized aromatic amines, their homologous derivatives and the sulphonic or carboxylic acids thereof, with 2-amino-8- naphthol-sulphonic acids including in this term their N substituted derivatives.

Some of these dyestuffs are already known, and have been described for dyeing wool, particularly for the production on wool of dyeings which are fast to milling, but it was not foreseen that these dyestufis could be used for dyeing regenerated cellulose silks. It is well known that the animal fibres such as wool are quite different from the cellulose fibres both in chemical and in physical properties and it is therefore all the more surprising that these simple wool colours should have value for dyeing regenerated cellulose silks.

We do not limit ourselves to the use of the monoazo colours but we also include within the scope of our invention certain primary disazo dyes. The dyestuffs which we find to be applicable in our process of dyeing regenerated cellulose materials in even level shades, may be represented by the following compound and Y represents hydrogen or a coupled residue having the structure in which R is derived from a second diazo compound. The 2-amino-8-naphthol sul phonic acids which we find advantageous as starting materials inpreparing these dyestuffs are sulphonated 2-amino-8-naphthols having the characteristic structure wherein R represents hydrogen, an alkyl .from a second diazo compound.

group or a phenyl or naphthyl residue. The monoazo dyestuffs may be represented by the following structurel formula.

wherein It, represents the coupled residue of a sulphonated 2-amino-8-naphthol and R represents a residue derived from a diazo compound. The primary disazo dyestuffs may be represented by the generic structural formula wherein R represents the coupled residue of a sulphonated Q-aminO-S-naphthol, R represents aresidue derived from a diazo com- 6 pound and R represents a residue derived The monoazo dyestufis are obtained in the known manner by coupling in alkaline or in acid solution. We have found that useful disazo colours can be obtained by coupling one molecule' of a diazo compound on to a sulphonic acid of 2-amino-8-naphthol, or its N substituted derivatives, in an acid medium and afterwards combining the monoazo colour in an alkaline medium with one molecule of the same or a different diazo compound. For example the diazo compound obtained from 218 parts of para nitroanilineortho sulphonic acid with 69 parts of sodium nitrite in the known way is coupled with 315 parts of 2- phenylamino-8-naphthol-6-sulphonic acid in an acid medium. Themixture so obtainedis made alkaline with sodium carbonate and to this is added a solution of the diazo compound obtained in the known way from 143 parts of a-naphthylamine. The coupling mixture is maintained alkaline until coupling is complete aften'whichthe dyestufl' is isolated by addition of salt. 'The structure is believed to be I sona on N.N\

N O CnmNH N :N

It forms a black powder which dyes viscose silk a blue violet shade. If 8-hydroxy-2-2- dinaphthylamine-6sulphonic acid be used in place of 2-phenylamino-8-naphthol-6-sulphonic acid in the above example the dyestufi's obtained dyes viscose silk a blue shade.

8 hydroxy-Q 2- dinaphthylamine G-sulphonic acid is prepared by heating 2-amino- 8-naphthol-(i-sulphonic acid with sodium bisulphite and B-naphthylamine. When the reaction is completed, the mixture is diluted and the product precipitated by the addition of common salt, filtered oil", dissolved in soda and filtered from unchanged B-naphthylaminc-and any ,BB-dinaphthylamine which may be present. The S-hydroxy-Q 2-dinaphthylamine-G-sulphonic acid is then precipitated as a white or greyish substance by acidifying the filtrate. Its probable structure is:

8 hydroxy-2 2-dinaphthylamine-3 6-disulphonic acid is similarly obtained from 2- amino-8-naphthol-3 6-sulphonic acid, sodium bisulphite and ,B-naphthyIamine.

For the preparation of 8-hydroXy-2: 1-dinaphthylamine- 6-sulphonic acid, 2-amino-8- naphthol-tS-sulphonic acid is heated with sodium bisulphite and a-n aphthylamine. After salting out the productas above described, the'sol-id is Washed with hydrochloric acid to remove unchanged a-naphtliylamine, and is then ready for use, no aa-(ll-' naphthylamine being formed. Its structure is probably SOaH- NHCeHu 100 parts of the regenerated cellulose silk goods are entered into the bath warm, after which the bath is heated nearly to the boil and dyeing is allowed to proceed nearly at the boil for about 1 hour. The goods are then removed, rinsed and dried. The resulting dyeing is a level deep brown shade, fast to washing, alkalis and to light.

The range of shades obtainable with monoazo dyes alone is further illustrated by the examples in the following table.

Arylamine diazotized Aminonaphthol coupled Coupling medium Shade gf p-anisidine 2-amino-8-naphthol-6-sulphonic acid Alkaline Reddish-brown o-anisidine 2-amino-8-naphthoI-G-sulphonic acid Alkaline Red 2:5-dichloroaniline 2-phenylamino-s naplithol-S-sulphonic acid Alkaline Brown S-nitro-o-anisidine Z-phenylamino-S-naphthol-6-sulphonic acid Acid Deep blue N aphthionic acid 2-pheny1arnino-8-naphthol-Gsulphonic acid Acid Violet brown z-chloro-p-toluidine-dsulphonic acid 2-phenylarnino-B-naphthol-S-sulphonic acid Alkaline Brown Aniline 8-hydroxy-2:l-dinaphthylamine-G-sulphonic acid Alkaline Brown m-aminobenzoic acid 8-hydroxy-2:2-dinaphthylaminc-G-sulphonic acid Alkaline Brown 2:5dichloroaniline 8-hydroxy2:2-'dinaphthylamine-3z6-disulphonic acid Acid Red A-chloro-o-anisidine 8-hydroxy-2:2'-dinaplitliylamine fizfi-disulphonic acid Alkaline Bordeaux Dehydrothio-p-toluidinesulphonic acid Z-Oanisoylamino-S-naphthol-G-sulphonic acid Alkaline Brown Dehydrothio-p-toluidinesulphonic acid 2-phenylamino-Ei-naphthol-fi-sulphonic acid Alkaline Brown p-chloroaniliue 2-p-chlorophenylamino-8-naphthol-fi-sulphonic acid Alkaline Light brown Dehydrothiotoluidinesulphonic acid 2 dinitroiihen y lamino) -8- naphthol -6- sulphonic Alkaline Reddish brown Dehydrothiotoluidinesulphonic acid 8-hydroxy-2:2- iinaphthyl-amino-o-sulphonic acid Alkaline Brown i:4-nitroaminodiphenylsulphide v 8-hydroxy-2:2'-dinaphthyl-amine-3:G-disulphonic acid Alkaline Brown p aminoacetaniline 2-ethylamino-B-nahpthol-dsulphonic acid Alkaline Reddish brown Dianisidineoxamic acid 2-pl1enylamino-8-naphthol-G-sulphonic acid Alkaline Reddish blue What we claim and desire to secure by Letters Patent is 1. The process of dyeing regenerated cellulose materials in level shades comprising the application of dyes having the probable formula YR N=NR wherein R represents the coupled residue of a sulphonated 2-amino8-naphthol, R represents a residue from a diazo compound and Y represents hydrogen or the structure N=N-R in which R is the residue from a second diazo compound.

2. The process of dyeing regenerated cellulose materials in level shades comprising the application of dyes having the following probable structural formula wherein R represents the coupled residue of a sulphonated 2-amino-8-naphthol having the characteristic structure NHR wherein R represents hydrogen, an alkyl group or a phenyl or naphthyl residue, R represents a residue from a diazo compound and Y represents hydrogen or the structure in which R is a residue from a second diazo compound.

3. The process of dyeing regenerated cellulose materials in level shades comprising the application of dyes having the following probable structural formula whereinlii represents the coupled'residue of a 2-amino-8-naphthol-6-sulphonic acid, R represents a residue from a diazo compound and Y represents hydrogen or the structural formula in which R is a residue from a second diazo compound.

4. vThe process of dyeing regenerated cellulose materials in level shades comprising the application of monoazo dyes obtained by coupling a Q-amino-8-naphthol-6-su1phonic acid having the characteristic structure HOaS tures.

JAMES BADDILEY.w PERCY GHORLEY. I RAINALD BRIGHTMAN. 

